For more than 150 years the Rosental Mitte site was used as a production and research facility for chemicals, dyes, pesticides and medicines. As a result of these former activities, there are harmful substances in the subsoil beneath the site. These are currently being removed.

To protect the public and the people working on the site from harmful substances and unpleasant odours, an airtight enclosure in the form of a protective tent was put up on the construction site. Air extracted from it passes through a controlled exhaust-air purification system.

To monitor the ambient air, the Office for Air Hygiene for both Basel cantons (abbreviated to LHA in German) has installed four air measuring stations around the construction site. These measuring stations draw in the outside air and direct it to measuring tubes and filters, which collect the pollutants for subsequent laboratory analysis.

To support the assessment of the analysis results, a weather station measuring wind direction and strength was installed on a roof on the site. The analysis results and the weather data can be viewed on the ‘Rosental Mitte Air Quality’ dashboard of the Open Government Dataportal of the Canton of Basel-Stadt.